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Vampire apocalypse calculator

A tongue-in-cheek epidemic model: seed a town with a few vampires and it runs a day-by-day predator–prey simulation — vampires feed and convert humans, while slayers and sunlight thin their ranks. It reports how many humans and vampires remain, and the day humanity falls, if it does.

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Enter Initial humans, Initial vampires, Feeding rate (attacks/vampire/day/human), Conversion rate (0–1), Vampire death rate (0–1), Simulation days and the Vampire apocalypse calculator works out Humans remaining, Vampires remaining, Day humanity falls straight away. For instance, with Initial humans = 10,000, Initial vampires = 10, Feeding rate (attacks/vampire/day/human) = 0.005, Conversion rate (0–1) = 0.3, Vampire death rate (0–1) = 0.02 and Simulation days = 90 it returns Humans remaining = 0, Vampires remaining = 2,958 and Day humanity falls = Day 3.

How to use it

  1. Enter your values: Initial humans, Initial vampires, Feeding rate (attacks/vampire/day/human), Conversion rate (0–1), Vampire death rate (0–1), Simulation days.
  2. Read the result instantly: Humans remaining, Vampires remaining, Day humanity falls.

Frequently asked questions

What does the Vampire apocalypse calculator actually compute?

It takes Initial humans, Initial vampires, Feeding rate (attacks/vampire/day/human), Conversion rate (0–1), Vampire death rate (0–1) and Simulation days and derives Humans remaining, Vampires remaining and Day humanity falls from them. The calculation is live as you type, so the result updates on every change.

What information do I need to provide?

6 values: Initial humans, Initial vampires, Feeding rate (attacks/vampire/day/human), Conversion rate (0–1), Vampire death rate (0–1) and Simulation days. Nothing else is required — no account, no file upload.

Can you show a worked example?

With Initial humans = 10,000, Initial vampires = 10, Feeding rate (attacks/vampire/day/human) = 0.005, Conversion rate (0–1) = 0.3, Vampire death rate (0–1) = 0.02 and Simulation days = 90, the calculator returns Humans remaining = 0, Vampires remaining = 2,958 and Day humanity falls = Day 3. Those figures come from running this exact tool, so you can reproduce them by entering the same values.

What happens if I enter larger values?

It moves a lot. Using Initial humans = 20,000, Initial vampires = 20, Feeding rate (attacks/vampire/day/human) = 0.006, Conversion rate (0–1) = 0.35, Vampire death rate (0–1) = 0.02 and Simulation days = 180 instead, Vampires remaining goes from 2,958 to 7,002 — which is why it is worth testing a few scenarios rather than trusting a single figure.

What does it give for smaller values?

Scaled down to Initial humans = 5,000, Initial vampires = 5, Feeding rate (attacks/vampire/day/human) = 0.005, Conversion rate (0–1) = 0.25, Vampire death rate (0–1) = 0.02 and Simulation days = 45, Vampires remaining comes out at 1,249. The relationship is worth checking at both ends before you rely on a single result.

When would I actually use this?

The questions no reference answers: what a meeting is costing while it runs, how many hours a commute has taken out of a year, how much detergent a load actually needs, and a few that exist for the pleasure of knowing — how many popcorn kernels would fill a room, what a hamster generates.

What is the most common mistake?

Quoting the playful ones as if they were measurements. A room filled with popcorn and a salary counted in bathroom breaks are arithmetic done honestly on premises chosen for fun; the number that comes out is exactly as solid as the assumption you fed it, which is the joke.

How accurate is it, and what are the limits?

Entirely fictional — a toy predator–prey model for fun, not epidemiology.

What is the difference between the Vampire apocalypse calculator and the Keyboard mileage calculator?

This one returns Humans remaining and Vampires remaining; the Keyboard mileage calculator returns Total keystrokes and Distance (miles). That is the whole difference — open the one whose figure you need.

Is there a tool for the next step?

Poop salary calculator is the closest one after this: Get paid to poop? Technically, yes. Enter your salary, your daily bathroom break and your working schedule, and this cheeky calculator reveals how much you earn on the toilet each day, each year and across the rest of your career — in the currency of your choice.

Further reading

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